Selective plating apparatus



Feb. 9, 1960 w. H. JACKSON SELECTIVE PLATING APPARATUS Filed May 3. 19566 Sheets-Sheet 1 INVENTOR. k J'czsa 7?.

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SELECTIVE PLATING APPARATUS Filed May 3. 1956 6 Sheets-Sheet 2 INVENTOR. M77147 (726130.

Feb. 9, 1960 w. H. JACKSON SELECTIVE PLATING APPARATUS 6 Sheets-Sheet 3Filed m a. 1956 IN VEN TOR.

Feb. 9, 1960 I w. H. JACKSON 2,924,564

SELECTIVE PLATING APPARATUS SSheets-Sheet 4 Filed May 3, 1956 IN VENTOR. Z1477? ficis'a 7r.

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w. H. JACKSON SELECTIVE PLATING APPARATUS Filed May 3, 1956 6Sheets-Sheet 5 Feb. 9, 1960 w. H. JACKSON 2,924,564

' SELECTIVE PLATING APPARATUS Filed May 3, 1956 6 Sheets-Sheet 6raw/ways.

U i c S s te 9 SELECTIVE PLATING APPARATUS William H. Jackson,Birmingham, Mich., assignor to The Utlylite Corporation, Detroit, Mich.,a corporation of Delaware Application May 3, 1956, Serial No. 582,426 8Claims. (Cl. 204 -204) The present invention relates generally toapparatus for the electrolytic treatment of articles. More speciiicallythe invention relates to a selective plating apparatus having a moreconvenient means for obtaining a desired thickness of metal plated onthe work.

I In the plating of metals the thickness of metal deposited in a giveninterval on a metal surface immersed in a plating bath usually cannot bereadily varied by changing the current density and other operatingconditions without impairing the quality of the coating, For thisreason, variations in coating thickness must generally be obtained byvarying the time of plating. In automatic types of plating machines itis not always possible, to obtain as wide a variation in the time ofimmersion as is sometimes required. While it is usually possible toreadjust the machine to anew time cycle, this is impractical or.impossible with most machines when successive loads of Worksimultaneously progressing therethrough require widely varying times ofimmersien in the plating bath.

The latter problem is often encountered in bulk plating wherein barrelor basket loads each containing a multitudeof small articles are passedthrough the machine. In commercial use, it is often desirable to be ableto process successive barrel loads of small articles which not only varywidely in size, shape and total surface area per unit of weight but alsowhich may require differing thickness of plated material. Heretofore,automatic machines have not been satisfactory in the handling of thistype of job lot plating and it has been the custom in many plating shopsto have auxiliary batch style equipment available to do this type ofwork. It would be desirable to have an automatic machine in which therecould be applied with equal facility the same thickness of plating towork having widely varying surface area per unit'weight or widelydiffering thicknesses of plating to identical parts. v

An automatic type of bulk plating machine is disclosed in my copendingapplication, Serial No. 448,084, filed August 5, 1954, wherein aplurality of horizontal, rotatable plating barrels are each suspended onan individual carriage by a set of. pantograph suspension arms; Thecarriages conduct the barrels through a series of treating stations, thepantograph arms permitting the barrels to be raised and lowered asrequired to pass over tank walls and to be rotated in both upper and:lower positions where necessary. The machine of the copendingapplication incorporates early-lift and/or delayed setdown means at someof its stations, the latter means being utilized to efiect a reductionin the immersion time (as compared to the standard machine cycle) forthe barrels in those stations. These early lift and delayed set-downliquid treatments wherein means are provided for more convenientlyvarying the thickness of plating or coating.

Another object is to provide an automatic apparatus for the plating ofwork wherein work of widely varying surface area per unit of weight maybe given the desired thickness of metal plating without disturbing thebasic automatic machine time cycle.

Another object is to provide an automatic plating ma-- chine whereinmeans are provided, which are brought into operation by movement of thework, for selectively energizing a greater or lesser portion of aplating section in order to secure variation in the time that each loadof work is exposed to the effects of the electric current.

Still another object is to provide an automatic plating machine whereineach work-supporting device such as a carriage is provided with acalibrated selector mechanism to enable the operator to set the time ofexposure to the current which the work on such carriage will receive inits traverse of the machine.

Yet another object is to provide an automatic plating machine wherein aplating section or station is provided which contains a plurality ofserially-arranged, separatelyelectrified plating positions and means areprovided for automatically energizing or de energizing a required numberof such positions as the work progresses through the plating station. i

It is also an object of this invention to provide a barreL type bulkplating machine of the automatic type wherein the work is contained inbarrels mounted on carriages and is moved through a plating stationcomprising a plurality of serially-arranged plating positions or cells,a number of such plating positions, which are in consecutive order,being provided with a separate circuit establishing means including ameans to energize and de-energize the circuit and each barrel carriagebeing provided with an adjustable device that can be positioned toenergize a desired number of the position circuits in the course of thetravel of the carriage through the succession of plating positions.

Other objects and advantages will be apparent, or will become apparent,in the following more detailed description of the invention taken inconjunction with the accompanying drawings.

'In the drawings:

Figure 1 is a 'plan view of the machine of this invention, partlyschematic, showing an illustrative arrangement of the tanks and themanner in which a plurality of vslork-containing barrels are conductedthrough the mac me;

Fig. 1A is a schematic plan view of the machine, as viewed in Fig. 1,showing an illustrative alignment, spacing and positioning of the switchrollers for normally-open switches; 1

Fig. 2 is an enlarged side view more clearly showing thebarrelsuspension arms, a switch actuator cam on the carriage, a drive unit forthe'cam mounted on the arms, and the individual position switch mountedatop the machine frame; i

Fig. 3 is a front View of one station of the machine, the view beingtaken as if looking in the direction ofthe arrow 3 in Fig. 2;

Fig. 4 is an enlarged front view looking at the outer end of thecarriage cam and its mounting and more clearly showing the manner inwhich the carriage cam engages the roller-equipped switch push rod, thisview being taken in the direction of the arrow 4 of Fig. 2; I

Fig. 5 is an enlarged front view of the position switch which isprovidedfor each of the individually-energized plating positions in theplating section;

Fig. 6 is a sectional view taken vertically through the switch along theline 6--6 of Fig. 5;

Fig. 7 is a plan View of the switch of Figs. and 6; Fig. 8 is aschematic representation of the individual electrical circuit providedfor each of the individuallyelectrified plating positions in the platingsection or sta- "tion; and Fig. 9 is a representation, partly schematic,of the f manner of operation of the calibrated cam drive unit and i ofthe manner and order in which the switches or their l roller-equippedarms are arranged or aligned along the side of the machine and themanner in which they are spaced across the zone of cam movement whenusing 'normally-open switches. In accordance with thepresent invention aselective machine for plating or other electrolytic treatment of .workis provided having an electrifiable section, such as a plating station,comprising a succession of seriallyarranged liquid-treating positionsthrough which the work is moved. Such liquid-treating positions eachhave a circuit means for applying an electric current to or across thework therein. The circuit means of each of a num- "ber of suchliquid-treating or plating positions which are in consecutive order arearranged to be separately energizable by being provided with a switch,circuit-breaker, 'or'other make-and-break means capable of establishingand interrupting the flow of the electric current. All such positionscould be provided for in this way, if desired. In the machine of thisinvention the work is carried by, or supported from, a work-carryingmeans such as a carriage, carrier, a traveling arm or arms, racks, etc.,or other members, which carrier means is mounted for travel through eachof the above-mentioned succession of liquid-treating positions. Themachine of this invention also is provided with a means for selectivelyenergizing and/or de-energizing a desired number of the individuallyenergizable liquid- .treating or plating positions in order to obtain adesired total time of exposure to the current (or total thickness "-ofdeposit) for each piece of work. This selective means is preferablymounted on or associated with each work carrier device and is soarranged that it is effective to selectively energize the individuallyenergizable plating positions in response to, or in the course of, themovement of the work carrier through the succession of positions. Theselective means preferably comprises a moveable or adjustable member foreach carrier which is move- 1 able in a given zone relative to the pathof travel of the work carriers and which can be positioned in such zoneso as to engage and actuate a predetermined number of the make-and-breakmeans of the various individuallyenergizable plating positions. Theselective means for each carrier also may include a calibrating meanssuch as a calibrated drive unit for moving and positioning the moveablecarrier member. The machine, of course, may also include, in addition tothe electrifiable section or plating station, a number of other types ofliquid-treating stations arranged to pre-treat or post-finish the work.

The selective means of this invention for controlling or determining thetime of exposure of the work to the effects of the electric current isespecially well adapted to bulk plating, and will be described moreparticularly herein in connection with the rotating-barrel type ofautomatic bulk plating machine, although it is to be appreciated that,it is equally applicable to other types of plating machines such as thesemi-automatic or automatic plating machines wherein traveling racks,frames, arms, carriers, etc. are used to suppont and carry the workthrough the machine. Referring now to the drawings, the machineillustrated therein is of the horizontal, rotating-barrel type. For acomplete description of such a machine reference should be had to myabove-mentioned copending application. Before proceeding to describe theselective plating means of this invention, however, it is believed abrief description of the general construction and mode of operation ofthe basic machine will provide a better understanding of the presentinvention. As shown in Fig. 1, the macarriage units or frames 38 aroundthe machine.

chine is of the return type having a plurality of tanks arranged arounda central frame. For purposes of illustration,'the unloading and loadingstations are located, respectively, at U and L in the upper right-handcorner of the machine, as viewed in Fig. 1, and the work travels aroundthe machine in the direction of the arrows.

When used for a cyanide zinc plating process, for example, the upperreach (Fig. 1) of the machine may also contain a cleaning section 10,which may consist of one or more individual tanks or stations whichneutralize, clean and rinse the work, a pickle tank 12, a rinse tank 14and a cyanide dip tank 16. The curved tank or station 18 extendingaround the left-hand end and along the bottom reach of the machine is anelongated plating station containing a plurality of seriallyarrangedplating positions 20. Tank 18 can be any length corresponding to anymultiple of the single celled positions 20. The remaining section 22 ofthe machine will contain individual tanks for a drain tank, a cold waterrinse, a bright (acid) dip tank, another cold water rinse tank and onthe curved right-hand end a final hot water rinse tank 24. Not all thesetanks or stations are illustrated in detail since we are concerned herewith only the electrified plating station 18 and the individual platingpositions 20 thereof.

As shown in Figs. 1 and 2, an upper guide track 80, consisting of achannel and an angle, is secured to the upper transverse central framemembers 32. Likewise, a lower guide track 34 composed of a channel andan angle, are secured to lower transverse frame members 36. The guidetracks 30, 34 extend completely around the machine and serve to guide aplurality of vertical The carriage frames (Figs. 2 and 3) are made up oftwo vertical members 40 each having on their top ends a bracket 42 onwhich is mounted a roller 44 which is received 'between the members ofthe upper guide track 30 and,

on their lower ends, a similar bracket 46 in which is mounted a roller48 which is received in a similar fashion in the lower guide track 34.The actual weight of the carriages is borne by the lower brackets 46wrich rest on the channel edge of the lower guide tracks 34 and gibs areprovided to prevent up and down movement of the carriages. The verticalcarriage frame members 40 are cross braced by three horizontal members50. Mounted in roller brackets 52 in the middle of the upper and lowermembers 50 is a single, vertical lift leg 54 having a roller 56 on itslower end. Pivotally secured to pairs of inwardly-projecting brackets 58rigidly secured near the top of the frame 38 are an upper pair 60 and alower pair 62 of pantograph suspension arms which project out over thetanks. Connecting the outer ends of each pair of upper and lower arms60, 62 is a vertically-disposed barrel support hanger arm 64. Ahexagonalshaped plating barrel 66 is rotatably suspended between thehanger arms 64. At the top end of the lift leg 54 there is secured anoutwardly projecting clevis bracket 70 in which is pivotally secured alink 72. The lower end of the latter is pivotally secured to a rod 68extended across between the upper pantograph arms 60.

The lift leg 54 is raised by an elevator rail 74 suspended along eachside of the machine opposite that portion of the machine wherein liftingof the barrels is required. As shown in Fig. 1, the rail 74 begins atthe exit end of tank or station 18 and extends around the machine toterminate at the entrance end of tank or station 18. Spring-loaded orweighted pick-up and drop-off fingers 76 are provided to engage anddisengage the lift leg rollers 56 during the movement of the barrels.The rail 74 is lifted by a mechanism more clearly described in theabove-mentioned copending application. When the lift legs 54 are liftedby the elevator rail 74, the arms 60, 62 of each carriage 38 are raisedlifting the barrels 66 out of the tanks on an arcuate path. Since thereis no lift rail and no tankwalls in the elongated plating tank 18,

the barrels therein remain immersed and are advanced while so immerseduntil their carriage lift legs 54 are picked up again by the elevatorrail fingers 76. If desired, however, the tank 18 could be made up ofone or more individual tanks. The carriages 38 are moved around themachine in a succession of movements by a conveyor chain, a guide railor plurality of sprockets 88 (Fig. 1) being provided to carry the chainaround the curved ends of the machine.

As shown in Fig. 3 a lineshaft 90 mounted along each side of the machinehas gears 92 mounted on it at intervals opposite each station requiringbarrel rotation. The bracket members 58 carried by each carriage 38 havemounted thereon a spring biased gear 94 which meshes with the lineshaftgears 92 and with a fixed gear carried by' a short shaft 98 mounted onthe brackets 58. The belt 102 is trained over an idler pulley 104 on oneof the lower pantograph arms 62 and over 'a large pulley 100 carried inthe upper end of one of the barrel hanger arms 64. The pulley 106actuates a gear train 108 carried on the barrel hanger arm 64 andterminating in a large ring gear 110 secured to the end of the barrel66. Rotation of the lineshafts 90 thus causes the barrels to rotate atall times in both upper and lower positions.

With the above brief description of the machine and its operation inmind, refer again to Figs. 2, 3 and 4. As will be seen best in Fig. 2,an upstanding gusset-type bracket110 is bolted on the top end of thevertical carr-iage frame member 40 and over the upper roller supportbracket 42. To the bracket 110 a second, triangularshaped, outwardlyprojecting bracket 112 is secured by welding and having secured on itsupper horizontal leg a slideway 114; In the latterthere is fitted aslide memher 116 having secured or screwed to its upper surfacean-elongated cam member 118 having its leading edge 120 (Fig. 4) taperedat about a 30 degree angle. As will appear most clearly in Fig. 4, theslide member 116 is' driven by a drive unit comprising a system ofchains and sprockets and a calibrated dial or turning wheel. The slidemember 116 has a bolt, pin or finger 122 projecting downwardly through alongitudinal slot 124 in the bottom ofslideway member 114. The lower endof finger 122 is secured between the plates of a small plate-link typeupper drive chain-126, it being secured therein by several of the chainconnector pins. Chain 126 is trained over an idler sprocket 127 anddrive sprockets 128' mounted in the face of the outwardly projectingbracket 112. As the chain 126 is driven forwardly and backwardly-theslide 116 and cam 118 will be moved correspondingly in slideway 114. Thepin 122, however, limits the movement of the slide 116 by engaging thesprockets 128. It should be noted that since the cams 118 and theirslideways are mounted on the carriages 38 which do not move up and down,the selector mechanism is eifective irrespective of the verticalmovement of the barrels 66'when they are lifted to clear tank walls.

The chain 126 is brought down over idler pulley 127 to pass around oneface of a double-faced sprocket 130 mounted for free rotation on the endof shaft 98 of the barrel rotate mechanism. A second similar chain 132is trained over the other face of sprocket 130 and is extended downalongside the suspension arms 60, 62 to pass over a small sprocket 134(Figs. 2 and 3) secured on the inner end of a'short shaft 136 mountedthrough the left-hand barrel hanger arm 64. On the outer end of shaft136 (as viewed inFig. 2) there is fixed a dial or turning wheel 138having a handle 140. A spring clip type of fixed pointer 142 is securedto a backing plate or bracket 144 (Fig. 3) rigidly bolted to the barrelhanger arm 64 and extends down over the edge of the dial to indicate itsposition. Thus, when the handle 140 is moved to rotate the dial 138,shaft 136 turns sprocket 134 and drives the lower chain. 132. Sprocket130 then rotates, driving upper chain 126 causing-the slide member 116and cam 118 to be advanced or retracted in slideway 114.

As mentioned above, each of the plating positions 20 in plating tank 18is provided with an electrical circuit and some of the positions arearranged to be individually energizable by means of an individualcircuit, the components of which appear most clearly in Fig. 8. Alongthe top of the machine there is provided a main electrical input cablefrom which a short branch lead 142 is led over to the input terminal 144of a circuit breaker type of switch 146 located adjacent each platingposition 20. More will be said about the structure of the latter switchbelow. From the output terminal 148 of the switch 146 a second shortlead 150 is extended down to be connected to a cathode bus bar section152. As appears most clearly in Fig. 8, a plurality of the bus barsections 152 are secured together by insulating connectors 154, withsuch a bus bar section being provided at each separately energizableplating position 20.

A spring-loaded cathode contact shoe 156 (Fig. 2) is mounted on abracket 158 carried on the inner side of each carriage unit 38 so as tobe in contact with the bus bar sections 152. Leading from the cathodecontact shoe 156 there is provided cable 160, which is supported on thebarrel suspension arms 60, 64 and extends down to pass into the interiorof the barrel 66 where it is connected to the usual internal barrel typecathodes in contact with the work contained therein. At each of theplating positions 20 helically coiled anode electrodes 162 are securedand filled with balls of zinc metal or other metal being plated. Thecircuit is completed by an anode bus 164 connecting the anodes with themain power input cable 140.

Since the amperage of the current carried by each of the above describedplating position circuits is heavy, the switch 146 is of necessarilyrugged design and incorporates arc suppressors. As will be seen in Figs.2, 3 and 6, the switch is mounted on a heavy box-like metal base orbracket mounted astride one of the upper transverse central framemembers 32 and comprising adjusting spacers 172 (for vertical height)and side channels 174 secured across the upper guide track members 30.Secured across the channels 174 is an upper base plate member 176 ofinsulating material. The switch 146 is shown to include two elongated,angle-shaped lower contact members 178 of copper secured by bolts to theinsulating base plate 176 and resiliently bound together againstspreading by several bolts 180, each of which is passed through thecontacts through an insulating bushing 182, a spring 183, an insulatingpad 184 and an insulating washer 186. The inner faces 188 of the upperends of the lower contact members 178 are cut on a taper to resilientlyreceive therebetween a similarly tapered knife blade upper contact 190.

The bolts also secure a plate 192 against the insulating pad 184. Theplate 192 has on each of its ends F an enlarged, rectangular portion 193through each of which is passed a guide bolt 194. Secured over the guidebolts 194 is the knife blade contact member 190. A coiled compressionspring 196 is disposed around each of the guide bolts 194 between theplate 192 and the blade member so as normally to urge the knife bladeout of contact with the lower contacts 178. Several curved, spring typeare suppressor clips 198 of metal, such as beryllium copper, are securedoverthe upper edge of the knife blade 190 with their lower spring-likeends making contact with a plate-like arc brush 200 secured to each.lower contact. Thus, when the upper knife blade 190 is drawn out ofcontact with the lower contacts 178 thespring clips remain in contactwith the brushes 200 and conduct the current until the knife blade isfully with-- drawn. The clip-like ends of the resilient arc suppressorclips 198 then quickly snap out of contact with the brushes 200 andeffect a cleaner break of the circuit.

The knife blade upper contact 190, supported by the springs 196 ispivotally secured betweena pair of links 202 having a spreader 204. Theupper ends of the links 202 are:

secured on a pin 206 passed through the end of a pivoted rocker arm 208.The arm 208 is insulated from'the 212 which is mounted near the outeredge of the insulating base plate 176. As seen in Figs. 2, 3 and 7, therocker shaft 210 extends outwardly toward the tanks. To the outer end ofshaft 210 there is secured a second rocker arm 213 which extendsparallel to the path of travel of the carriages 38. On its other end,rocker arm 213 carries a vertical rod 214 slidably secured therein by anut and cotter key 216. On the lower end of rod 214 there is secured anangle-shaped bracket 218 in which is secured, by means of a shoulderscrew 219, a roller 220. A compression spring 222 is mounted around therod 214 between the rocker arm 213 and the roller mounting bracket 218so as to normally urge the roller 220 in a downwardly direction. Asshown in Fig. 4 the roller 220 makes contact with the tapered leadingedge 120 of the switch-engaging cam 118 so that the roller will belifted vertically. As it does so, the spring 222 is compressed untilrocker arm 213 is caused to pivot upwardly rotating rocker shaft 210.Rotation of the rocker shaft 210 causes rocker arm 208 to pivot or rockdownwardly, forcing the knife blade contact 190 down between lowercontacts 178. This completes the circuit shown in Fig.

Operation As was mentioned above, the plating section of the machine ofthis invention contains a plurality of individual plating positions 20,some of which are provided with a separate electrical circuit forelectrifying the work. The plating barrels pass through all suchstations but the work is plated only in those stations in which thecircuits are energized. For reasons specified below, it is usuallyundesirable to pass freshly .plated work through plating solutions withno current flowing. It is preferred, therefore, that the plating occurat the exit end of tank 18 and the de-energized plating positions, ifany, occur at the entrance end of plating tank 18.

For convenience, therefore, one or more of the adjacent positions 20near the exit end of tank 18 need not be provided with switches 146 orindividual circuit means so that plating occurs on the work of eachbarrel as it passes therethrough. Thus, there is plated in thesepositions on each barrel of work a certain minimal thickness of deposit,which thickness will vary with the different types of work, for example,from 0.0001 to 0.001 inch in thickness. This minimal thickness ofplating should preferably be less than is required for most worknecessitating the energization of one or more additionalimmediately-preceding positions 20 to build the thickness of the coatingto the desired value. For purposes of illustration, Figs. 1A and 9 ofthe drawings show that the last three positions 20 of plating tank 18have been arranged to plate all the time so that the Zero position ofdial 138 (i.e. cam 118 fully retracted, Fig. 9) has been given thenumbers 13-15. There are, therefore, twelve individually electrifiablepositions 20 in the illustrated machine. These numbers are for purposesof illustration only and it should be realized that all of the platingpositions can be individually electrified and that any proportionthereof may be arranged without switches so as to plate all work passingtherethrough. A large plating machine of this type could have in asingle plating section as many as 20, or even a greater number of theindividual plating positions 20, including as many as 10' or morepositions arranged to plate all the time.

a sau The. reasons forv using this type of setupis thatthe zinc andcadmium cyanide plating solutions have the power, when no current isflowing, to dissolve away a freshly-applied zinc or cadmium plating. Theacidic plating solutions, such as those of copper, nickel, chromium andothers, also react adversely on metal immersed therein with no currentflowing, such as atendency to etch a freshly plated deposit, to deposita precipitationtype of coating of inferior quality on either the baremetal or the freshly plated surfaces, which coating interferes withadhesion of later coatings applied with current, or to passivate thebare metal or previously-applied plated coating so that tightly adherentplated coatings of the desired weight can not be subsequently applied.Bare metal, however, can be safely immersed in cyanide type solutionswithout current flow since the solution only has a tendency to clean themetal. The selective plating machine of this invention, therefore, isespecially useful in connection with zinc and cadmium cyanide typeplating solutions or with any other plating solution which does notexhibit the above adverse effects or which is inhibited against theseeffects.

One of the switches 146 is, therefore, located above or adjacent to eachof the plating positions 20 which it is desired to energize orde-energize. In Figs. 1A and 9, the first twelve of the stations 20 areshown as being so provided (numbers 1 to 12 on dial 138). Each ofvertical switch push rods 214 for these twelve positions is positionedon its rocker shaft 210 so as to project outwardly toward the carriages.They are arranged, however, in a more or less uniform stepwise orstaggered spacing across the zone of travel X of the cam 118. This sortof spacing is shown diagrammatically in Figs. 1A and 9, the spacingappearing in Fig. 1A being exaggerated for purposes of illustration. Thedistance X of Fig. 9, of course, is the sum of the clearance distancesrequired for the rollers 220 of the number of switches 146 employed. Thedistance Y is the stroke of the slide memher 116 and, of course, must besubstantially equivalent to the distance X. Distance X, therefore, isthe zone through which the cam 118 must be movable in order to becapable of actuating all the switches. Fig. 1A shows that the switchroller 220 of the switch at the first plating position 20 at theentrance end of plating section 18 (No. 1) is positioned so as to beclosest to the longitudinal centerline of the machine (or with relationto the carriages it is the greatest distance inwardly therefrom) and theswitch roller 220 of the last individually-electrifiable position 20(number 12) projects the greatest distance from the longitudinalcenterline of the machine. This order is shown in Fig. 9 wherein the cam118 is shown fully retracted so as to clear the roller 220 of positionNo. 12 (only the continuously-electrified positions 13 to 15 plating).In this position of the cam the dial 138 is shown in the zeroed positionmarked 13-15. If it is desired to electrify station 12, cam 118 wouldhave to be advanced in toward the machine frame to engage the roller 220of station 12. As dial 138 is turned in the direction indicated by thearrow so as to bring the numbers 12, 11, 10, etc. under the pointer 142,it will be seen that the chains move in the directions indicated toproject the cam 118 inwardly of the machine into the zone of cammovement X. When the number (1) on dial 138 is under the pointer thedrive pin 122 attached to slide member 116 engages the inner ofsprockets 128 and it is necessary to reverse the rotation of the dial toretract the cam 118.

The above illustrated alignment of the switch push rods and theirrollers is preferred for normally-open switches. When normally-closedswitches are employed it is preferable that the staggered arrangement ofthe push rods 214 on the rocker shafts 210 be reversed, that is, the rod214 of position No. 1 will project the greatest distance, and the rod ofposition No. 12 will project the least distance, from the longitudinalcenterline of the machine. Dial 138 could then be calibrated in reverseorder .to read directly in position numbers which will be plating (ornot engaged by cam 118).

a The utility of the plating machine of this invention will become moreevident when it is seen that an operator stationed at loading stationwill load each barrel as it arrives from unloading station U. After hehas loaded the barrel he will check the setting of dial 138 to see if acorrect number of stations will be energized to plate the desiredthickness of metal on the particular work he has just placed in thebarrel. If not, he rotates the dial to the correct setting before thebarrel moves on to the first of the plating positions in tank 18.Knowing the minimal thickness of coating plated on the work in thecontinuously-electrified positions 13 to 15 and the average incrementadded in each of the individually- ,electrifiable positions 20, it is asimple matter to compute the correct number of the stations 20 to beenergized to yield the desired total thickness of coating. If all theplating positions 20 are individually energizable he, of course, needsonly to know the average increment of plating thickness which will bedeposited in each position. In commercial operations calibration curvesor charts could be prepared of plating thickness versus number ofstations for each general type of work.

Let it be supposed that each barrel is loaded with a given weight ofwork. .When the individual pieces are small, for example, small screwsor springs, etc., the total surface area to be plated represented by agiven Weight is relatively larger than when the same weight of largerarticles such as stampings or heavy bolts, etc. are to be plated. Ifboth types of work were immersed for the same length of time under theeifects of current, the smaller articles would receive a thinner depositthan the larger. Likewise, it may be necessary in some cases to plate amuch thicker deposit on one barrel of a given type of work than isrequired for the succeeding or preceding barrel of the same work. It canbe seen, there fore, that the machine of this invention makes itpossible to handle widely varying types of work and to plate on eachtype exactly the desired thickness of metal. The machine thus makes itpossible for the plating shop to handle small job lot plating on aneconomical automatic basis. It is also valuable in handling large volumetypes of work, the advantage residing in not having to readjust thecontrols of the machine when changing from one type of work to another.

What is claimed is: a

1. In an apparatus having a plurality of work-supporting means mountedfor travel through a succession of liquid-treating positions, a circuitmeans for each of a number of said positions and each including ananode, an electric current source connected thereto and means forestablishing and interrupting the flow of electric cur* rent betweensaid anode and said work-supporting means, an engaging means for eachsaid work-supporting means each mounted so as to be moveable in a givenzone relative to the path of travel of said work-supporting means, saidcurrent establishing and interrupting means being arranged along thepath of travel of said work supporting means and spaced in a stepwisemanner across the zone of movement of said engaging means, and means oneach said work supporting means for moving its respective engaging meansto a position in said zone wherein it will actuate a predeterminednumber of said current establishing and interrupting means in responseto the movement of said work-supporting means through said succession ofliquid-treating positions.

2. In an apparatus having a plurality of work-supporting means mountedfor travel through a succession of serially-arranged liquid-treatingpositions, a circuit means for each of a number of said stations andeach including an anode, an electric current source connected to saidanode, a switch means efiective to establish and interrupt the flow ofcurrent from said anode to said work-supporting means, each said switchmeans having an actuable member located adjacent the path of travel ofsaid work-supporting means, an engaging means mounted on each saidwork-supporting means so as to be moveable in a given zone relative tothe path of travel of said work-supporting means, the said actuablemembers being arranged along said path of travel of said work-supportingmeans and spaced in a stepwise manner across the said zone of movementof said engaging means, and means on each said work-supporting means formoving its respective said engaging means to a position in said zonewhere it will engage a predetermined number of said actuable members inresponse to the movement of said work-supporting means through saidplating positions.

3. In an apparatus having a plurality of work-supporting carriagesmounted for travel through a succession of liquid-treating positions, anelectrical circuit means for each of a number of said positionsproviding electric current to each said position and including, anelectrical switch mounted adjacent each said position, each said switchbeing electrically connected, respectively, to the saidv circuit meansof its said position so as to be effective in establishing andinterrupting the flow of electric current therein, a switch engaging cammeans mounted on each said carriage so as to be moveable in a given zonerelative to the path of travel of said carriages, said switches of saidpositions being arranged along the path of travel of said carriage unitsin a stepwise manner so as to be each actuable at a given position insaid zone of movement of said switch engaging cam means, and means oneach said carriage for moving its respective said switch engaging cammeans to a position wherein it will engage and actuate a preselectednumber of said switches in response to the movement of said carriagethrough said plating positions.

4. Apparatus comprising a plurality of seriallyarranged liquid-treatingstations including a plating station containing a plurality ofserially-arranged plating positions, a plurality of work-supportingcarriages mounted for travel through said stations, circuit means foreach of said plating positions for subjecting the work therein to theaction of an electric current including an anode, current supplyingmeans connected to said anode and means connected to said carriages tocomplete said circuit, and a switch for each of at least a number ofsaid plating positions which are in adjacent order starting from theentrance of said plating station and each effective to establish andinterrupt the flow of said current in its respective circuit means, anengaging cam mounted on each said carriage and each moveable in a givenzone relative to the path of travel of said carriages, an actuablemember for each said switch positioned in said zone of cam movement,said actuable members being aligned, with respect to each other and tothe direction of travel of said carriages, in a stepwise fashion acrosssaid zone of cam movement so that each said cam can engage and actuateat predetermined positions thereof a predetermined number of saidactuable members.

5. In an apparatus having a plurality of work-supporting carriagesmounted for travel through a succession of liquid-treating stationsincluding a plating station containing a plurality of serially-arrangedindividual plating positions, a separate circuit means for each saidplating position for applying an electric current to the work thereinincluding an anode, and a current source connected to said anode, and anelectric switch located at each said position and electrically-connectedinto the respective said circuit means so as to be effective toestablish and interrupt the flow of said current, a switch-engaging cammounted on each said carriage so as to be moveable in a given zonetoward and away from said switches, an actuating arm on each said switchprojecting into said zone of cam movement, the projecting ends of thesaid actuating arms being arranged, with respect to the path of travelof said carriages, in a uniformly-spaced stepwise manner across saidzone of cam movement, a cam drive unit associated with each saidcarriage for moving the respective said cam, and a calibrated meansconnected to said drive means toenable the positioning of each said camso as to engage a predetermined number of said dividual platingpositions, circuit means for each said plating position including ananode, a current source connected to said anode, 'and an electricalswitch located at each of a number of said plating positions which arein consecutive order starting at the entrance end of said platingstation, each said switch being effective to establish and interruptflow of electric current in the said circuit means of its said platingposition; an engaging member mounted on each said carriage so as to bemoveable in a given zone relative to the path of travel of saidcarriages, in actuable element for each said switch effective to openand close said switch, said actuable elements being arranged along thepath of travel of said carriages and spaced in a graduated manner acrossthe said zone of movementof said engaging members, and a drive-meansassociated with eachsaid barrel and its suspension'for moving theengaging member thereof to a position in said Zone where it will engageand actuate a predetermined number of said actuable elements as saidbarrel and its carriage travel through said plating positions.

7. Apparatus as defined in claim 6 wherein the said barrel is mounted onsuspension arm, the said drive means comprises a system of chainstrained over sprockets mounted on said suspension arms and said engagingmeans comprises a plate-like member mounted for movement in a slidewayand arranged to be reciprocated by said drive means.

8. Apparatus as claimed in claim 5 wherein the said electrical switchesare of the normally-open type and their said actuating arms are soarranged that on engagement by each of said engaging cams on saidcarriages the said switches will be closed to establish flow of currentin said circuit means.

References Cited in the file of this patent UNITED STATES PATENTS1,809,138 Miller June 9, 1931 2,626,621 Curtis Jan. 27, 1953 2,724,691Hakes Nov. 22, 1955

1. IN AN APPARATUS HAVING A PLURALITY OF WORK-SUPPORTING MEANS MOUNTEDFOR TRAVEL THROUGH A SUCCESSION OF LIQUID-TREATING POSITIONS, A CIRCUITMEANS FOR EACH OF A NUMBER OF SAID POSITIONS AND EACH INCLUDING ANANODE, AN ELECTRIC CURRENT SOURCE CONNECTED THERETO AND MEANS FORESTABLISHING AND INTERRUPTING THE FLOW OF ELECTRIC CURRENT BETWEEN SAIDANODE AND SAID WORK-SUPPORTING MEANS, AN ENGAGING MEANS FOR EACH SAIDWORK-SUPPORTING MEANS EACH MOUNTED SO AS TO BE MOVEABLE IN A GIVEN ZONERELATIVE TO THE PATH OF TRAVEL OF SAID WORK-SUPPORTING MEANS, SAIDCURRENT ESTABLISHING A INTERRUPTING MEANS BEING ARRANGED ALONG THE PATHOF TRAVEL OF SAID WORK SUPPORTING MEANS AND SPACED IN A STEPWISE MANNERACROSS THE ZONE OF MOVEMENT OF SAID ENGAGING MEANS, AND MEANS ON EACHSAID WORK SUPPORTING MEANS FOR MOVING ITS RESPECTIVE ENGAGING MEANS TO APOSITION IN SAID ZONE WHEREIN IT WILL ACTUATE A PREDETERMINED NUMBER OFSAID CURRENT ESTABLISHING AND INTERRUPTING MEANS IN RESPONSE TO THEMOVEMENT OF SAID WORK-SUPPORTING MEANS THROUGH SAID SUCCESSION OFLIQUID-TREATING POSITIONS.